Hanna Instruments HI 904, Quick Start Manual

Page: 147 / 180

Method ID: HI9901EN
Bromine Index of Aromatic Hydrocarbons
Adaptation of ASTM D1492-08
Titrator Application Methods: General Applications – r. 1.0
Description :
Method for the determination of bromine index of
bromine-reactive substances. This method typically
applies to aromatic hydrocarbons with only trace
amounts of olefins (alkenes) and having bromine
indexes less than 1000. For samples with a bromine
index greater than 1000, it is recommended to dilute
the sample with a suitable solvent.
Electrodes:
x
HI 76330 Double Platinum Pin Electrode
x
HI 900517 Generator with Diaphragm
-or-
x
HI 900518 Generator without Diaphragm
Reagents:
x
Coulometric Bromine Index Reagent without
Mercury, prepared in a 1-L volumetric flask:
x
600 mL glacial acetic acid
x
260 mL methanol
x
140 mL KBr solution (119 g/L)
x
Deionized water, to 1 L
Other Accessories:
x
A clean, dry 1-mL syringe
x
A clean, dry 22-gauge, 6” non-coring septum
penetration needle
x
GL 45-Thread Reagent Bottle
x
1-L volumetric flask
x
100-mL graduated cylinder
Procedure:
x
Setup titrator according to the instruction manual.
Remove desiccant from the desiccant cartridges
on the reagent/waste bottles and on the generator.
x
Press “ Select Method ” from the main screen. Use
the arrow keys to highlight ‘HI9901EN BrIndex of
Aromatics’ and press “
Select ”.
x
Prepare 1 L of coulometric bromine index reagent
according to the Reagent List. Add to a GL 45-
thread reagent bottle.
x
Connect the reagent bottle top assembly to the
reagent bottle according to the manual. Do not
use desiccant in the desiccant cartridge.
x
Prepare the titration vessel according to the
manual. Dispense enough reagent from the
reagent bottle to fill the vessel to the “min” line
(about 100 mL).
x
Press “Start/Stop” to pre-titrate the reagent.
x
Fill the syringe and needle with the sample.
x
Weigh the syringe, needle and sample.
x
Press “ Start Analysis ”. You will be prompted to
enter the sample size.
x
Enter the Estimated Bromine Index. The titrator
will recommend the optimal sample size to be
added to the titration vessel. Dispense the amount
provided from the optimal sample size into the
titration vessel through the septum using the
needle. Pay attention not to get any sample on
the electrode or vessel walls. If necessary swirl
the titration vessel by hand.
x
Clear the needle of residual sample by in taking a
small volume of air from the titration vessel. If a
“hanging drop” of sample is seen on the end of the
needle, dip the end of the needle briefly in the
solvent.
x
Remove the needle from the titration vessel and
weigh the syringe again in order to determine the
added sample mass (by difference of the two
measurements.)
x
Use the numeric keypad to enter the exact weight
and press “
Enter” to start the analysis.
x
At the end of the titration the “Sample Analysis
Result” screen is displayed. The results are
expressed in
mg (Br)/100g .
Method Parameters :
Name: BrIndex of Aromatics
Method Revision: 1.0
Type: Bromine Index
Pre-Analysis Stir Time: 30 Sec
Stirring Speed: 1600 RPM
Stirbar Type: Medium
Reagent: BrIndex Reagent
Sample Parameters:
Sample Determ.: Normal
Sample Name: DefaultSample
Sample Type: Mass
Sample Size: 0.5000 g
Control Parameters:
Titration Speed: Slow
Standby Mode: Enabled
Standby Duration: 12:00 hours
Imposed Current: 10 uA
End Point Value: 300.0 mV
Generator Current Mode: Auto
Signal Averaging: 2 Readings
Termination Parameters:
Maximum Duration: 2400 sec
Maximum Bromine Consumed: 25.000 mg
Term. Criterion: mV End Point
End Point Stability Time: 40 sec
Result Unit: mg/100g
Calculations :
Bromine Consumed: Br(
mg
)
Final results units: mg/100g
Sample mass: 1.0000 g
mg/100g
bromine (
m
g)
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